I've played it through three times, and still no clue who the killer is. Every new playthrough though, I was surprised by the depth of the storytelling. The first time I completely forgot about the smell, but using this opened the case up like crazy, which was very neat. Good job!
I am thrilled that you're enjoying it!
I would ask for a spoiler, I really wanna know whodunnit, but kinda breaks the point of a whodunnit game, eh?